<Note> This page is still updating. Check back soon for more update.
Introduction to Neuroscience
Neuroscience in Singapore
Selected Top Publications (First author from Singapore)
Jeanne M.M. Tan, Esther S.P. Wong, Donald S. Kirkpatrick, Olga Pletnikova, Han Seok Ko, Shiam-Peng Tay, Michelle W.L. Ho, Juan Troncoso, Steven P. Gygi, Michael K. Lee, Valina L. Dawson, Ted M. Dawson, Kah-Leong Lim, "Lysine 63-linked ubiquitination promotes the formation and autophagic clearance of protein inclusions associated with neurodegenerative diseases," Human Molecular Genetics, vol. 17, no. 3, pp. 431–439, Feb. 2008. DOI: 10.1093/hmg/ddm320
Abstract: Although ubiquitin-enriched protein inclusions represent an almost invariant feature of neurodegenerative diseases, the mechanism underlying their biogenesis remains unclear. In particular, whether the topology of ubiquitin linkages influences the dynamics of inclusions is not well explored. Here, we report that lysine 48 (K48)- and lysine 63 (K63)-linked polyubiquitination, as well as monoubiquitin modification contribute to the biogenesis of inclusions. K63-linked polyubiquitin is the most consistent enhancer of inclusions formation. Under basal conditions, ectopic expression of K63 mutant ubiquitin in cultured cells promotes the accumulation of proteins and the formation of intracellular inclusions in the apparent absence of proteasome impairment. When co-expressed with disease-associated tau and SOD1 mutants, K63 ubiquitin mutant facilitates the formation of tau- and SOD-1–positive inclusions. Moreover, K63-linked ubiquitination was found to selectively facilitate the clearance of inclusions via autophagy. These data indicate that K63-linked ubiquitin chains may represent a common denominator underlying inclusions biogenesis, as well as a general cellular strategy for defining cargo destined for the autophagic system. Collectively, our results provide a novel mechanistic route that underlies the life cycle of an inclusion body. Harnessing this pathway may offer innovative approaches in the treatment of neurodegenerative disorders.
Affiliated: National Neuroscience Institute, Johns Hopkins University School of Medicine, Harvard Medical School, National University of Singapore
Cheng Wang, Jeanne M. M. Tan, Michelle W. L. Ho Norazean Zaiden Siew Heng Wong Constance L. C. Chew Pei Woon Eng Tit Meng Lim Ted M. Dawson Kah Leong Lim, "Alterations in the solubility and intracellular localization of parkin by several familial Parkinson's disease‐linked point mutations," Journal of Neurochemistry, vol. 92, no. 2, pp. 422–431, Mar. 2005. DOI: 10.1111/j.1471-4159.2005.03023.x
Abstract: Mutations in the parkin gene, which encodes a ubiquitin ligase, are currently recognized as the main contributor to familial forms of Parkinson's disease (PD). A simple assumption about the effects of PD‐linked mutations in parkin is that they impair or ablate the enzyme activity. However, a number of recent studies, including ours, have indicated that many disease‐linked point mutants of parkin retain substantial catalytic activity. To understand how the plethora of mutations on parkin contribute to its dysfunction, we have conducted a systematic analysis of a significant number of parkin point mutants (22 in total), which represent the majority of parkin missense/nonsense mutations reported to date. We found that more than half of these mutations, including many located outside of the parkin RING fingers, produce alteration in the solubility of parkin which influences its detergent extraction property. This mutation‐mediated alteration in parkin solubility is also associated with its propensity to form intracellular, aggresome‐like, protein aggregates. However, they do not represent sites where parkin substrates become sequestered. As protein aggregation sequesters the functional forms away from their normal sites of action, our results suggest that alterations in parkin solubility and intracellular localization may underlie the molecular basis of the loss of function caused by several of its mutations.
Affiliated: National Neuroscience Institute, National University of Singapore, Ngee Ann Polytechnic, Johns Hopkins University School of Medicine
Andrew B. West, Darren J. Moore, Catherine Choi, Shaida A. Andrabi, Xiaojie Li, Dustin Dikeman, Saskia Biskup, Zhenshui Zhang, Kah-Leong Lim, Valina L. Dawson, Ted M. Dawson , "Parkinson's disease-associated mutations in LRRK2 link enhanced GTP-binding and kinase activities to neuronal toxicity ," Human Molecular Genetics, vol. 16, no. 2, pp. 223–232, Jan. 2007. DOI: 10.1093/hmg/ddl471
Abstract: Mutations in the leucine-rich repeat kinase 2 gene ( LRRK2 ) cause late-onset Parkinson's disease indistinguishable from idiopathic disease. The mechanisms whereby missense alterations in the LRRK2 gene initiate neurodegeneration remain unknown. Here, we demonstrate that seven of 10 suspected familial-linked mutations result in increased kinase activity. Functional and disease-associated mutations in conserved residues reveal the critical link between intrinsic guanosine triphosphatase (GTPase) activity and downstream kinase activity. LRRK2 kinase activity requires GTPase activity, whereas GTPase activity functions independently of kinase activity. Both LRRK2 kinase and GTPase activity are required for neurotoxicity and potentiate peroxide-induced cell death, although LRRK2 does not function as a canonical MAP–kinase–kinase–kinase. These results suggest a link between LRRK2 kinase activity and pathogenic mechanisms relating to neurodegeneration, further supporting a gain-of-function role for LRRK2 mutations .
Affiliated: Johns Hopkins University School of Medicine, National Neuroscience Institute
Brain Computer Interface (BCI)
Brain Computer Interface (BCI) is an advanced communication technology that enables humans to communicate with machine through direct or non contact interact via brainwave signals. According to Wikipedia, research on BCI started in 1970 funded by the United States government agency National Science Foundation (NSF) and Defense Advanced Research Projects Agency (DARPA).
#neuroscience #BCI #brain #communication #i2r #singapore